Making a String

1000ms

262144K

Description:

You are given an alphabet consisting of n letters, your task is to make a string of the maximum possible length so that the following conditions are satisfied:

the i-th letter occurs in the string no more than a_i times;
the number of occurrences of each letter in the string must be distinct for all the letters that occurred in the string at least once.

Input:

The first line of the input contains a single integer n (2 ≤ n ≤ 26) — the number of letters in the alphabet.

The next line contains n integers a_i (1 ≤ a_i ≤ 10⁹) — i-th of these integers gives the limitation on the number of occurrences of the i-th character in the string.

Output:

Print a single integer — the maximum length of the string that meets all the requirements.

Sample Input:

3
2 5 5

Sample Output:

Sample Input:

3
1 1 2

Sample Output:

Note:

For convenience let's consider an alphabet consisting of three letters: "a", "b", "c". In the first sample, some of the optimal strings are: "cccaabbccbb", "aabcbcbcbcb". In the second sample some of the optimal strings are: "acc", "cbc".

Informação

Provedor Codeforces

Código CF624B